02_19_2014 - Updated weapon damage upgrades to new upgrade path format and prepared code for other upgrades.
02_19_2014 - Multishot bullet upgrades now available in shop.
02_20_2014 - Fixed upgrade path bug where indexes didn't reset when restarting the game.
02_20_2014 - Fire rate upgrades implemented in shop. Does not affect actual fire rate yet.
02_20_2014 - Ship now shoots bullets based on fire rate attribute.
02_20_2014 - Updated enemy health to be more balanced with new ship power.
02_20_2014 - Cleaned up drawEnemy function.